Dear Statalist.

I have a dataset of dyads in groups in long format.
I need to generate a variable "dyad_id" that identifies distinct dyads in the dataset.

This simple toy dataset illustrates the problem.
The group identifier is "project_id" and the members in each dyad are identified by "member_id".
project_id member_id dyad_id
1 1 1
1 2 1
2 3 2
2 4 2
3 1 3
3 3 3
4 1 1
4 2 1

Any and all input on this problem would be greatly appreciated.

Thanks!

Sincerely,
Erik